1. Field of the Invention
Aspects of the present invention relate to a battery pack, and more particularly, to a battery pack capable of preventing a defective appearance and label lifting.
2. Description of the Related Art
Rechargeable secondary batteries are more economical than disposable dry cells. In recent years, low-volume and high-capacity secondary batteries have been developed, which are widely used as power supplies for portable electronic devices, such as cellular phones, camcorders, notebook computers, and the like. Secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries.
Lithium secondary batteries are widely used, because of their small size, high capacity, high operating voltage, and high energy density per weight. Lithium secondary batteries may be classified as can-type lithium secondary batteries or pouch-type lithium secondary batteries, depending on the shape of a casing, which accommodates an electrode assembly having a negative electrode plate, a positive electrode plate, and a separator. The can-type lithium secondary batteries may be further classified as cylinder-type lithium secondary batteries or prismatic-type lithium secondary batteries.
The casing of the can-type lithium secondary batteries is generally formed of a metal, such as aluminum, and has a cylindrical shape, a prismatic shape, or a pillar shape with rounded edges. The can has an upper opening through which an electrode assembly is inserted and an electrolyte is injected. A cap assembly is used to seal the opening of the can, resulting in a sealed bare cell.
The pouch-type lithium secondary batteries have a pouch casing that accommodates an electrode assembly, on a lower surface of the casing. The lower surface is covered with an upper surface of the pouch casing, and sealing portions are formed by bonding edges of the upper and lower surfaces, resulting in a bare cell.
The bare cell is electrically connected with a protecting circuit board, which includes a protecting device to prevent overcharges, over-discharges, over-currents, and the like. In general, the electrical connection between the bare cell and the protecting circuit board is made via a lead. Such a secondary battery may be called a core pack.
A hard-pack-type battery pack is formed by inserting the core pack into an additional external case. An inner-pack-type battery pack is formed by filling a space between the bare cell and the protective circuit board with a resin, then labeling the core pack with a thin label. The core pack may include a holder, in which the protective circuit board can be seated.
In order to protect the protective circuit board from the outside, a case can be used to cover the protective circuit board. The appearance of a battery pack is formed by forming a protrusion that extends from an out surface of the holder and forming a hole in the case that corresponds to the protrusion. The protrusion is then inserted into the hole. As the protrusion extends outside from the holder, a defective appearance and label lifting can occur when attaching a label.